Sylvania



UNITED STATES PATENT OFFICE.

GEORGE A. NELLIS AND FLORENCE S. WVEISSER, OF ALLEGHENY, PENN- SYLVANIA.

TRANSMITTER-DIAPHRAGM.

SPECIFICATION forming part of Letters Patent No. 539,636, dated May 21,1895.

Application filed March 11, 1895. Eerial No. 541,334. (No model.)

To 60% whom it may concern.-

Be it known that we, GEORGE A. NELLIs and FLORENCE S. WEIssER, ofAllegheny, in the county of Allegheny and State of Pennsylvania, haveinvented a new and useful Improvement in Transmitter-Diaphragms, ofwhich the following is a full, clear, and exact description.

Ourinvention relates to the diaphragms employed for transmitting soundin electrical apparatus, such as telephones, microphones, andbattery-transmitters, and it is designed to afford a diaphragm for thispurpose, which shall transmit sound with greater clearness and shall notdeteriorate by continued use. The ordinary iron disk which is used forthese purposes will not retain its polished surface and hence willabsorb a portion of the sound which it receives, instead of reflectingthe same.

We have discovered that when aluminum is alloyed with a small portion ofanother metal or metals, a diaphragm made of the resulting compositionpossesses the quality of transmitting sound to a remarkable degree, itbeing very sonorous and resilient in character. On account of itsresiliency, it retains its shape much better than does the ordinarydiaphragm, and hence does not need adjustment toward or from other partsof the apparatus, resulting from a change of shape effected bycontinuous use. The metals which we prefer to combine with the aluminumare iron, nickel, or silver, or a combination of these metals, in anycase buta small percentage of the supplementy metal being necessary.Thus, if iron is used, about two or three percent. is preferred. 1fnickel is used, preferably about four or five per cent. is employed, andabout the same per cent. in the case of silver. WVhen nickel or silveris employed, we preferably also add a small per cent. of iron.

The composition we prefer is the nickelaluminum alloy, which ispreferably in about the following proportions: aluminum, ninetyfour percent; nickel, four per cent; iron, one per cent; silicon, one per cent.A plate thus formed of aluminum with a small per cent. of another metalor metals will receive and retain a high polish, and hence not absorb aportion of the sound received. The acid of the breath will not affect ortarnish the surface, and the composition is exceedingly springy andsonorous.

Many variations may be made in the proportions of the various metals andin the metals used for the addition, without departing from ourinvention; since What we claim is l. A transmitter-diaphragm consistingof a plate composed of a mixture of aluminum and nickel; substantiallyas described.

2. A transmitter-diaphragm composed of aluminum with a small percentageof nickel and iron; substantially as described.

In testimony whereof we have hereunto set our hands.

GEO. A. NELLIS. FLORENCE S. WEISSER. Witnesses:

W. B. CORWIN, H. M. Coawrn.

